Start with a well-prepped surface. Inspect the area with a good lighting source to find any cracks, stains and other inconsistencies in the surface you plan to paint. If you're painting over new drywall or want to use a light paint over a dark paint, you'll need to apply a primer coat first.
Paint and primer in-one formulations can reduce the need for primer. Some interior paints are self-priming, meaning it's not necessary to apply a separate coat of primer first – particularly paints that include 100 percent acrylic latex binder, which boosts adhesion to surfaces. However, some experts suggest using separate primer anyway to get better coverage from your top coat.
Water-based latex paint is best for most situations. Water-based paint wears better over time, is easier to clean up and has fewer odors than oil-based interior paint.
Consider a low-VOC or no-VOC paint. Paint fumes can cause headaches and nausea. Long-term exposure has also been linked to liver and kidney problems. If you'll be working in an area with little ventilation, a paint low in VOCs -- chemicals that are linked to health problems -- might be an especially good idea.
Decide on a finish. There are several types of interior paint finishes. Gloss and semi-gloss paints are great for areas that require frequent cleaning, such as kitchen cabinets and walls. Satin paint has low shine and also is easy to clean. Eggshell, with its barely discernable gloss, is a good choice for bedrooms, living rooms and family rooms. Flat and matte finishes have almost no reflective quality, making them good choices for walls and ceilings with irregularities.
How to buy enough paint. Multiply the length of the walls all around the room by their height to get square footage. Add the square footage of the ceiling (if you're painting the ceiling). Subtract out the square footage of the ceiling (if you're painting the ceiling). Subtract out the square footage of the doors and windows, then add 25 percent to that figure. Manufacturers provide information about the coverage you can expect under normal circumstances on the paint can, but a gallon of top-quality paint should cover 350 to 450 square feet. Be sure to buy enough paint, because you'll want extra for touch-ups later. Remember that lighter colors over darker ones will usually require more coats than the other way around.
Top quality interior paints can cost twice as much as budget paints (or more), but premium paints proven to provide thorough coverage in just one or two coats can actually cost less in the long run. Cheaper paint requiring more than two coats for even coverage mean that you'll be purchasing more paint to cover the same surface area, negating the cost savings. Additionally, premium paints that resist stains and fading, mildew, and other wear and tear will last longer, so you won't have the need to repaint as frequently. Remember that price isn't correlated with quality in every case, so you'll want to evaluate quality considerations such as coverage, surface smoothness, and durability alongside costs.